[Elecraft] Elecraft 70cm transverter, K3 and repeater access tones?

[w8zn at comcast.net]

While I don't have a 432 Elecraft transverter, I have had a lot of experience with DEM transverters and K3's over the last year. If you change the crystal in the transverter to use 26 MHz for 432 then 30 MHz would be 436 and this works well with a couple of caveates. The bandpass filters start to cut off pretty sharply around 27 MHz and you will find the rx is down about 6 db, mostly not a problem since most transverters have ample gain. On the transmit side, I have found  the output is reduced to about -6 dbm and isn't as adjustable as it is at 28 MHz, probably ALC action with reduced output from the bandpass filters. I have used it and it works well, you just have to play with the levels and as you go up in frequency, you have to watch that you don't overdrive the transverter. DEM offers a crystal that allows their transverter to cover 435 with a 28 MHz IF, this equates to a 25 MHZ IF for 432 and the 12m bandpass should work well for this but once again, as you go up, the bandpass will be dropping until you reach around 27 MHz. 



I have considered re-tuning the 10m filters down to give flatter response at 26MHz giving away 28.8 and up which I never use anyway but haven't decided which way to go. Since the FM band in the US is 440 to 450, it's a waste since nothing you do is ever going to give you 20 MHz of bandwidth. I just keep a 70cm FM transceiver around and just use the K3 for weak signal work around 432. 



Hope this helps. 



Terry - W8ZN 


----- Original Message ----- 
From: "John Lemay" <john at carltonhouse.eclipse.co.uk> 
To: "G4ILO' 'Julian" <julian.g4ilo at gmail.com>, elecraft at mailman.qth.net 
Sent: Tuesday, February 17, 2009 5:35:03 AM GMT -05:00 US/Canada Eastern 
Subject: Re: [Elecraft] Elecraft 70cm transverter, K3 and repeater access  tones? 

There are switched bandpass filters prior to the 10w PA stage, which are 
also in circuit before the transverter output. I expect that the 28 to 30MHz 
filter would not be suitable right up to 32MHz. 

So I guess an extension of transmit capability to 32MHz would not be on the 
cards. 

Regards 

John G4ZTR 

-----Original Message----- 
From: elecraft-bounces at mailman.qth.net 
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Julian, G4ILO 
Sent: 17 February 2009 09:04 
To: elecraft at mailman.qth.net 
Subject: Re: [Elecraft] Elecraft 70cm transverter, K3 and repeater access 
tones? 




wayne burdick wrote: 
> 
> The XV432 itself *does* cover the full 70-cm range. If you use it with 
> a rig that covers 28-32 MHz, you'll have this capability. But the K3 
> only covers 28-30 MHz. 
> 

Could not the K3 be transmit-enabled up to 32MHz? Are the bandpass filters 
too narrow to permit this? It seems like potentially a very easy solution. 

----- 
Julian, G4ILO. K2 #392  K3 #222. 
http://www.g4ilo.com/ G4ILO's Shack   http://www.g4ilo.com/blog.html G4ILO's 
Blog    http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 
-- 
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